Micro grid power distribution unit

ABSTRACT

The techniques described herein include for forming a power grid array with multiple power generators coupled to a power distribution unit. The power distribution unit is adapted to monitor operational data from each of the power generators to perform load balancing among the generators and to optimize the performance of the power grid array. A microgrid network is also provided within the power grid array to enable communication among the power distribution unit and the multiple generators in the array. This communication facilitates monitoring of the power grid as well as receiving and storing the operational data from each of the generators in the grid. The microgrid network can then be used to communicate the operational data over one or more connected networks allowing users to remotely access the power grid and to monitor and control the operational characteristics of the generators.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to (1) U.S. Provisional PatentApplication No. 61/600,987, filed Feb. 20, 2012, entitled “POWERDISTRIBUTION UNIT FOR POWER GRID MANAGEMENT”, (2) U.S. ProvisionalPatent Application No. 61/600,986, filed Feb. 20, 2012, entitled “REMOTEMONITORING AND CONTROL IN A POWER GRID”, and (3) U.S. patent applicationSer. No. 13/400,532, filed Feb. 20, 2012, entitled “METHOD AND SYSTEMFOR GENERATOR CONTROL”, the disclosures of which are each incorporatedby reference herein in their entirety.

In addition, the following U.S. patent applications (including this one)are being filed concurrently, and the entire disclosures of each isincorporated by reference in their entirety into this application forall purposes: (1) application Ser. No. 13/772,218, filed Feb. 20, 2013,entitled “POWER GRID REMOTE ACCESS”; and (2) application Ser. No.13/772,229, filed Feb. 20, 2013, entitled “MICRO GRID POWER DISTRIBUTIONUNIT”.

FIELD OF THE INVENTION

The embodiments described herein relate generally to power generatorsystems. More particularly, the embodiments relate to forming a powergrid array of multiple power generators coupled with a powerdistribution unit.

BACKGROUND

A micro-grid (or “microgrid”) is a localized grouping of electricitygenerators, energy storage, and electrical loads that normally operateconnected to a traditional centralized grid (“macrogrid”). Powergeneration and the electrical loads in a microgrid are usuallyinterconnected at low voltage. From the point of view of the gridoperator, a connected microgrid can be controlled as if it was oneentity. Microgrid generation resources can include fuel cells, wind,solar, or other energy sources, including local power generators. Themultiple dispersed generation sources and ability to isolate themicrogrid from a larger network can provide highly reliable electricpower.

Power grid systems generally require load profile data including theoperating characteristics of all of the power generators connected tothe grid to be gathered and analyzed to optimize the microgrid'sconfiguration. But, heretofore, during normal operation of microgrids,information about the load characteristics and generator performance isnot normally available without connecting it with external equipment andcustom software. In addition, conventional generators typically includea display to observe performance characteristics, fault conditions, oilpressure data, and the like; however, the data is never stored anywhereso it is lost when the generator is shut down or a user clears the faultor warning conditions.

In addition, microgrids are more fuel efficient than standalone orparallel generator systems and they provide a robust, redundant powersource. But microgrids are generally more complex. As a result,conventional microgrid systems require that entire networks (e.g.,micro-grid arrays) be shut down to disconnect one generator from thegrid for servicing.

SUMMARY

Embodiments described herein include systems, methods, and apparatusesfor forming a power grid array comprising multiple power generatorscoupled together with a power distribution unit such that theoperational data from each of the power generators can be monitored andthe performance of the power grid can be optimized. In one embodiment,this is accomplished using a computer built into the power distributionunit. This operational data can then be stored and accessed later foranalysis to optimize the power grid array's configuration. Theoperational data of the generators in the power grid can be used toperform load balancing among the generators to coordinate the amount ofpower each of the generators should contribute to the electrical load.For instance, the operational data can be used to automatically shutdown one or more of the connected generators to conserve fuel or toaccommodate a changing electrical load profile. In addition, the poweroutput lines from each of the plurality of generators in the power gridarray can be coupled together using a load sharing cable to drive theoverall electrical load of the power grid. In one embodiment, a safetywire is embedded into each of the power output lines of the generatorsto ensure that each generator connected thereto is disabled when it isshut down.

Embodiments described herein are also adapted to form a microgridnetwork within the power grid array that provides a means ofcommunication among the power distribution unit's computer and themultiple generators in the array. This communication facilitatesmonitoring of the power grid as well as receiving and storing theoperational data from each of the generators in the grid. The microgridnetwork can then be used to communicate the operational data over one ormore connected networks via a network port coupled with the powerdistribution unit (“PDU”) computer that allows users to remotely accessthe power grid and to monitor the operational characteristics of thegenerators. Users can access the microgrid using a data processingdevice of some kind, such as a laptop computer, tablet, or a mobilecommunications device. A hardwired connection or a wireless router canbe plugged into the network port for remote access. In one embodiment,the network port exposes the operational data as a web server that canbe accessed on the Internet. In addition, the network port can befurther adapted to receive commands from the user's device over thenetwork for controlling the generators in the grid.

These and other details of embodiments of the invention are described inthe following description, claims, and figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of at least certain embodiments of the inventioncan be obtained from the following detailed description in conjunctionwith the following drawings, in which:

FIG. 1 depicts an example block diagram of a power generator systemaccording to one illustrative embodiment.

FIG. 2 depicts an example block diagram of a power distribution unitcoupled with a plurality of power generators in a power grid arrayaccording to one illustrative embodiment.

FIG. 3A depicts an example flow chart of a process of monitoring andcontrolling a power grid array according to one illustrative embodiment.

FIG. 3B depicts an example flow chart of a process of forming amicrogrid network in a power grid array according to one illustrativeembodiment.

FIG. 4A depicts an example screen shot of display for monitoring powergenerators in a power grid according to one illustrative embodiment.

FIG. 4B depicts an example screen shot of display for accessing powergenerators in a power grid according to one illustrative embodiment.

FIG. 4C depicts an example screen shot of display showing theoperational characteristics of a power generator in a power gridaccording to one illustrative embodiment.

FIG. 4D depicts a second example screen shot of display showingadditional operational characteristics of a power generator in a powergrid according to one illustrative embodiment.

FIG. 5 depicts an example block diagram of a data processing system uponwhich the disclosed embodiments may be implemented in certainembodiments.

DETAILED DESCRIPTION

Throughout this description for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be apparent, however, toone skilled in the art that the present invention may be practicedwithout some of these specific details. In other instances, well-knownstructures and devices are shown in block diagram form to avoidobscuring the underlying principles of the described embodiments.

I. Operational Data Collection

The techniques introduced herein are adapted to form a power grid arrayby coupling together a plurality of power generators with a powerdistribution unit such that the operational data from each of the powergenerators can be monitored, analyzed, and optimized. In one embodiment,this is accomplished using a computer built into the power distributionunit. This operational data can then be stored and accessed later foranalysis to optimize the microgrid's configuration. The operational dataof the generators in the power grid can be used to perform loadbalancing among the power generators in the grid to coordinate theamount of power each of the generators should contribute to theelectrical load. For instance, the data can also be used toautomatically shut down one or more of the connected generators toconserve fuel.

The techniques described herein are also adapted to form a microgridnetwork within the power grid array that provides a means ofcommunication among the power distribution unit's computer and themultiple generators in the array. This communication facilitatesmonitoring of the power grid as well as receiving and storing theoperational data from each of the generators in the grid. The microgridnetwork can then be used to communicate the operational data to thecomputer in the power distribution unit as well as over one or moreconnected networks via a network port coupled with the computer. Themicrogrid network thus facilitates users to remotely access the powergrid using a data processing device of some sort, and to monitor theoperational characteristics of the generators.

For instance, users can access the microgrid network using a laptopcomputer, tablet, or a mobile communications device as examples. Otherdevices, computers, or data processing devices can be used. A hardwiredconnection or a wireless router can be plugged into the network port forremote access. In one embodiment, the network port exposes theoperational data as a web server that can be accessed on the Internet.In addition, the network port can be further adapted to receive commandsfrom the user's device over the network for controlling the generatorsin the grid. In at least certain embodiments, the microgrid network isaccessed using an Internet Protocol (“IP”) address of the power gridarray. The computer of the power distribution unit can also be accessedby its IP address.

As described above, the power distribution unit is capable of monitoringall of the generators in the power grid with a single computer (ormultiple computers in some embodiments). The power grid data can bemonitored remotely by users using various data processing devices (e.g.,laptop, PDA, table PC, smart phone, etc.). The power grid data can beshared on a network such as a LAN, WAN, or other network configuration.Users can access a hard drive of the PDU by its IP address and downloador view power grid data without preloading any particular software ontothe user's device. The data can be in spreadsheet format, documentformat, or other commercially available or proprietary format. The usercan view, download, and manipulate data once access to the PDU isestablished. Security measures may be implemented as required as wouldbe appreciated by one of ordinary skill in the art. In some cases, thePDU includes a computer that accesses and collects the operational datafrom one or more of the gensets. In other cases, each of the generatorsin the grid has a built-in computer that collects and stores theoperational data and can communicate and share the data over themicrogrid network via a wired or wireless connection. In such cases, acontrol panel inside each generator can be configured to export theoperation data to the PDU.

Certain embodiments incorporate grid monitoring Ethernet connections andautomatic data logging using the computer built into the PDU. Themonitoring can begin at the time the power grid is brought online. Thedata logging computer can also detect new generators when they areattached to the grid and can then log data from those additionalcomputers as they are brought online. In certain embodiments, this canbe accomplished using an integrated controller area network (“CAN”) businterfaced with a Modbus for the operational data monitoring. The PDUcomputer can log operational data from connected generators to a solidstate disk (or other memory) and can be remotely accessed to view anddownload the data over a network connection such as an Ethernetconnection. The network port (e.g., Ethernet port) can be connected tothe user's data processing device over a wired or wireless network. Forinstance, the user's device can be a tablet PC, laptop, or smart phoneapplication connected via an external wireless router for wirelessaccess to the operational data from a remote location.

FIG. 1 depicts an example block diagram of a power generator system. Inthe illustrated embodiment, generator 100 includes a controller 105coupled with a battery 110 to provide DC power 102 to the controllerfrom a DC power connector 103 via a DC power receptacle 106. Controller105 is further coupled with a digital signal 101 received on a digitalsignaling cable (not shown) via a digital receptacle 104. In oneembodiment, only the amount of DC power 102 necessary to charge thebattery 110 that powers the controller 105 is provided for each powergenerator 101 in the power grid. This is advantageous because power canbe conserved within the power grid.

In addition, digital signal 101 coupled with the controller 105 viareceptacle 104 is used for data and control signals for communicationsamong and between the generators connected to the power grid as well asthe computer at the PDU. The operational data gathered and stored by thecontroller 105 can be sent to the PDU computer for monitoring andanalysis using the digital signaling cable upon which the digital signal101 is coupled to. In the illustrated embodiment, the controller 105 ofgenerator 101 can be used to couple the power generated by the generatorto the load 117 via load line 120. In one embodiment, the load line 120is referred to as a power output cable of the generator 101. Thisembodiment further shows that a safety wire 130 coupled with the poweroutput load line 120 of the generator via an interlock receptacle 115.In one embodiment, the safety wire 130 and the power output load line120 are incorporated into the same cable.

Multiple of the generators 101 are coupled together with a PDU to form apower grid array. FIG. 2 depicts an example block diagram of a powerdistribution unit coupled with a plurality of power generators in apower grid array. In the illustrated embodiment, the power grid arrayincludes a plurality of generators 201-205 coupled with inputs 1 through5 of PDU 255 via power output load cables 1 through 5 respectively.Generators 201-205 each include the components of generator 101discussed above with respect to FIG. 1. DC power can be coupled to thegenerators 201-205 via the DC power line 252. As discussed previously,this DC power may be used to charge the batteries of the generators. TheDC power over line 252 can also be used to power up the computer 260onboard the PDU 255 via the DC input 230. Other sources of power arealso contemplated within the scope of the techniques described herein.In the illustration, PDU 255 includes a set of outputs 1 through 5,which in at least certain embodiments, are adapted to provide low-levelpower distribution to end users directly from a plurality of the outputsof the power distribution unit. PDU 255 is configured to provide thislow-level without requiring additional PDUs connected at the outputs 1to 5 as is required in conventional systems.

In addition, the digital signal 101 discussed above can be provided overthe digital paralleling cable 250, which is coupled to the digital inputof each of the power generators in the power grid as well as to acontrol input 231 of the PDU 255. This digital signaling cable 250provides communications within the power grid among the generators201-205 as well as the computer 260 of the PDU via control input 231. Inone embodiment, the digital communications are used to provide theoperational data of the generators 201-205 to the PDU for monitoring,storage, and analysis. The computer 260 can then provide the operationaldata and other characteristic data for the generators in the array via anetwork port such as Ethernet port 232. In addition, commands can bereceived from users over a network coupled with the network port 252 tocontrol certain functionality of the generators connected to the powergrid. In this manner, a microgrid network can be established within thepower grid array such that operational data can be collected, stored,and provided to users over a wired or wireless connection; and likewise,command and control signals can be received from users remotely over oneor more connected networks.

FIG. 3A depicts an example flow chart of a process of monitoring andcontrolling a power grid array. In the illustrated embodiment, process300 begins at operation 301. In that operation, a power grid array isformed by coupling multiple generators together with the powerdistribution unit of the present disclosure. This allows the computer onthe power distribution unit to monitor the power grid array (operation302) and to receive operational data from the connected generators(operation 303). The operational data can then be stored (operation 304)and used to analyze, optimize, and control the generators in the powergrid (operation 305). In one embodiment, the multiple generators can besynchronized automatically using the techniques described herein suchthat the amount of power contributed by each of the generators can becoordinated to drive an electrical load profile. This operational datacan be saved as log files in memory of the computer in the powerdistribution unit. The operational data can further be used to balancethe electrical load among the multiple generators and can be used todetermine that one or more of the generators should be shut down toconserve fuel or to adapt to a changing electrical load profile.

Process 300 continues at FIG. 3B, which depicts an example flow chart ofa process of forming a microgrid network in a power grid array. In theillustrated embodiment, a microgrid network is formed within the powergrid array (operation 311). As above, the power grid array is formed bycoupling multiple generators together with the power distribution unitof the present disclosure. This arrangement allows the computer on thepower distribution unit to monitor the power grid array (operation 312)and to store operational data received from the connected generators inthe power grid (operation 313). Once the operational data is stored atthe PDU, it can be communicated over a network (operations 314). Atoperation 315, commands for controlling the generators in the power gridarray can also be received from users over the network using a dataprocessing device coupled with the network.

In one embodiment, this can be done by coupling the microgrid networkwith a network port configured to communicate over one or more networks.For instance, the network port can be configured to plug into a wirelessrouter to transfer data via Wi-Fi, Bluetooth, or equivalent network. Forinstance, the network port is an Ethernet port and the communicationscan be made over the Internet. The network port can be configured toconnect to a wired or wireless connection for remote access by a userhaving a data processing device capable of sending and receiving dataover a network. In other embodiments, the microgrid network can beaccessed via a wireless network to view or download the operational datawirelessly from a user's device. In at least certain embodiments, thenetwork port exposes the operational data of the microgrid network as aweb server that can be accessed over the Internet. The microgrid networkcan be accessed, for example, using an Internet Protocol (“IP”) addressassociated with the power grid array. In other embodiments, the computerin the PDU can also be accessed by its IP address. Such access to userson a network can be provided in certain embodiments without preloadingany specialized software onto the user's device. This completes process300 according to one example embodiment.

The monitoring tracking capabilities described above can provide apre-alert of a potential problem prior to generator failure. Statisticalanalysis of generator usage over time can provide myriad means ofimproved generator usage in terms of efficiency, diagnostics,preventative maintenance, and the like. To illustrate this method with apractical example, the oil pressure in a generator may be low for sixweeks followed by a seized motor. The customer may try to return thegenerator to the manufacturer for a refund claiming that the generatorwas defective. With access to the generator operational data, themanufacturer is able to determine that, for example, the customerneglected to address the low oil pressure during the prior six-weekperiod and failed to add any oil, which may be useful to know toestablish liability. In another example, a service person can accessdata trends over time to determine if there is an oil leak, thegenerator is burning oil, the water temperature is too high, extra fuelis being burned, or the like. In conventional systems, this type of datais fleeting (e.g., passes in real time) and is then lost. In certainaspects, the generators or PDU can automatically collect this data andprovide operational data trends over time to help diagnose potentialproblems, or to analyze the data offline or at another time.

The service person could also analyze power load profiles over a periodof time (e.g., 24 hours) to determine if the generators in the powergrid are being properly matched to a given load. In some cases, thegenerators may be oversized for a small load and thus inefficientlyutilized for the particular load profile. In another example, a serviceperson can access a signature of a load profile over several days. Thismay be useful when a particular load profile is relatively constant on aday-to-day basis, but then there is one particular day that exhibitedanomalous results. For example, a generator may provide more currentthan normal at a military base camp when hot water heaters are poweredup in the morning, which may indicate a short or other circuit failure.

With the wireless data transfer capabilities, the PDU can wirelesslyinterface with common consumer electronic devices (e.g., tablet personalcomputers, smart phones, etc.) to transfer power grid operational datafor remote monitoring. The PDU can include a computer that collects theoperational data and stores it in any suitable format. In some cases,the PDU can automatically begin logging all operation data for the powergrid at start up. The generators in power grid array can be connectedtogether to share an overall electrical load and to communicate witheach other to coordinate how much power each generator should contributeto the load. A load sharing cable (not shown) can connect the generatorstogether, allow them to communicate with each other, and enable trackingand monitoring of the operating or performance characteristics data ofthe generators such as their oil pressure, water temperature, fuellevel, generator voltage output, potential faults or warnings (e.g.,voltage spikes, over voltage, under frequency, etc.).

Wireless access to the PDU provides a convenient way to monitor theoperation of the power grid remotely from a distance away. As describedabove, the PDU provides a capability to connect external Ethernetdevices, such as a Wi-Fi router, so that the power grid can be on awireless grid, wireless network, or hardware network, to allow consumerelectronic devices (e.g., iPAD™, iPhone™, or the like) to connect to thenetwork and retrieve data. In some embodiments, an application can bedownloaded from a onto the user's device. Such an application can enablea user to type in the IP address of the power grid to gain access formonitoring and downloading of power grid data. For example, a user maywant a particular generator to run for four (4) hours or the user maywant to program the grid such that it automatically selects a particulargenerator to run based on a number of operating hours it has on it. Inanother example, the user's device may show that there are three 45 kWgenerators on the grid and a 10 kW load to calculate power efficiencyand usage data. The user's device can be configured to download a logfile from the power grid. In some cases, this may be imported intocommon spread sheet applications (e.g., Excel, Numbers, etc.). Othertypes of data logs can be exported as well as would be appreciated byone of ordinary skill in the art with the benefit of this disclosure. Ifa service person wants to troubleshoot a generator in the grid, thatperson can view what states the generator has gone through and identifywhere the problem is. This data can be downloaded onto the user's deviceand reviewed at a later time, or emailed or downloaded to anothercomputer, etc. For example, if a soldier in Afghanistan is on the phonewith technical support in the United States, that soldier can email alog file to the support personnel to give them a clear picture of thegenerator operating history over any desired period of time. As such,there are myriad types of information that the user's device can accessin addition to monitoring the grid from anywhere in the vicinity of anetwork connection such as Wi-Fi. In addition, the user's device canremotely access multiple microgrids provided within wireless range.

All of the operating and performance characteristics can be madeaccessible on one or more of the generator screens or the PDU, and canbe collected, stored, and cataloged at any time by a computer (e.g., thegenerator controllers or the onboard computer, or the like).Conventional generators typically include a display to observeperformance characteristics, fault conditions, oil pressure data, andthe like; however, the data is never stored anywhere so it is lost whenthe generator is shut down or a user clears the fault or warningconditions. As described above, providing a means to collect thegenerator data for later analysis provides many advantages. Theoperational data can be accessed via a display on a generator (e.g., onthe control panel, on the generator chassis, etc.), on the PDU, or otherpoint on the power grid array.

FIG. 4A depicts an example screen shot of display for monitoring powergenerators in a power grid. In the illustrated embodiment, a list 401 ofonline generators 402 is provided in a main screen 400A of anapplication for monitoring the microgrid. In this case, only generator 2is powered on. Generator 2 is rated 403 at 30 KW in the illustratedembodiment. Additional performance characteristics 405 are also shown.Main screen 400A further includes a settings tab 409 which can be used,in at least certain embodiments, to drill down into further details ofthe operational characteristics of the generators connected to the grid.

FIG. 4B depicts an example screen shot of display for accessing powergenerators in a power grid. In the illustrated embodiment, settingsdisplay screen 400B includes a field 412 for users to type in the IPaddress of the power grid to access it over a network using the user'sdata processing device. In this example, the power grid is located on anetwork port 414 of the PDU designated as port 502. A field 422 is alsoprovided for users to type in the IP address of the PDU to access itover a network as well. Settings display screen further includes a listof log files 425 that have been previously received from the grid andstored in the PDU.

FIG. 4C depicts an example screen shot of display showing theoperational characteristics of a power generator in a power grid. In theillustrated embodiment, display screen 400C includes configurationinformation 431 for one of the generators in the grid. Such detailedinformation, including operational data, includes (1) the three-phasevoltage 432 of the particular generator, (2) the operating frequency433, (3) fuel level 434 (e.g., gas, diesel, propane, etc.), (4) totalpower generated 435 (as well as power generated for each phase), and (5)a listing of log files 436 that have been previously obtained from thegrid and stored in the PDU. Display screen 400C further includes a tab439 to navigate back up the list of generators.

FIG. 4D depicts a second example screen shot of display showingadditional operational characteristics of a power generator in a powergrid. Other operational data can also be displayed including, but notlimited to: (1) which generators are running, which are not; (2) whichcontactors are supplying power as well as the quantity of power; (3) howmuch power each generator is contributing to the power grid; (4) thewater temperature in the generator radiators; (5) the oil pressure ofthe generators; (6) systems faults and warnings during operation; (7)the amount of total power available on the power grid; (8) thepercentage load on the grid; (9) which generators are contributing tothe load and which are not; (10) the total number of hours a generatorhas been running; (11) overall grid performance including a sum total ofall generators; and (13) any real-time or snapshots of the performanceof the generator or power grid.

II. Integrated Power and Safety Cable

Generally, multiple generators or generator sets (“gensets”) are notdirectly connected together without some protection device that protectsusers or equipment from shock hazards. In conventional systems wherethere is no backup or redundant power generator, two generators can beconnected together in parallel where each have both a power cable and acontactor interlock cable (safety cable) for each of the generators. Inthese conventional two-generator systems, killing the power in onegenerator would be safe since the contactor interlock cable isdisconnected and the power could not back feed through to the generatorthat was powered down. But in power grids with multiple generators anddistributed architectures (e.g., micro-grid arrays), there can be, forexample, situations where four generators are running and a fifth isshut down. In these cases, since all five of the power output cables ofthe five generators are coupled together via a shared cable to drive theelectrical load, power can feedback from the generators that are runningthrough the shared power output cable and can back feed into the poweroutput cable of the fifth generator that was shut down. This can presentan electrocution hazard since power is still present on the connectordue to a misconnected cable.

In some embodiments, the PDU is configured to combine the outputs of allthe microgrid connected generators while providing a safe way todisconnect any one generator from the grid for service. This contrastswith conventional systems, which can require that entire networks (e.g.,micro-grid arrays) be shut down to disconnect one generator from thegrid for servicing. The PDU described herein is designed with connectorsand cables configured to connect to one or more gensets together and caninclude internal disconnects (e.g., decouplers) to automaticallydisconnect the power at power output cables to provide for safe removalof one or more generators from the power grid without having to powerdown the grid. To do this, in at least certain embodiments, the PDUincludes generator isolation control where the power output cable andthe safety cable are the same cable. This system prevents accidentalfaulty wiring of a safety circuit in the system that could result inelectrocution hazards. Certain embodiments further include failsafecontactor position light-emitting diodes (“LEDs”) or other equivalentindicators to alert users to warn against live voltage on inputs andprevent hazards from failed contactors.

In some cases, a disconnect relay is configured to disconnect the powerto the power output cable of one or more generators in the grid whilethe remaining generators on the grid are still active. For instance, amicro-grid array may have five generators connected to a PDU, where eachone of the generators has an output power cable. Each generator canfurther include five more cables coming for a protected relay via aninterlock cable. But a problem can arise where the power cables andinterlock cables can look the same and a person could easily mistake onecable for the other such that the protective device may not be connectedto the same input that the intended generator is connected to. In such ascenario, the protection device may be rendered useless because it maybe controlled from the wrong generator, thus creating an electrocutionhazard. As a result, although the generator power cable may be shutdown, the contactor cable can still be powered.

The techniques described herein resolve this problem in at least certainembodiments by embedding the safety wire in the same cable (or cableconnector) as the power cables used to output power to the electricalload. Essentially, the control for the protection device can be combinedwith the power output cable for the generator making it is impossiblethat the protection device and the generator will be connected togetherimproperly because both features are incorporated into one cable. Inanother embodiment, the PDU includes an automatic disconnect contactorthat electrically disconnects a power output cable from the generatorwhen the generator is shut down without requiring manual switches,controls, or the like. This configuration provides a failsafe systemthat ensures that, when a particular generator is off, the contactor atthe remote PDU is also disabled and the power cable is disabled from thePDU back to the generator, which, for all practical purposes, eliminatesthe risk of electrocution.

Other novel features of the contactor/power cable system include a lowerweight than competing units, improved design of handles that are alsoused for securing cables, legs that allow for release from muddysurfaces, better impact protection, and failsafe contactor position LEDsthat prevent hazards from failed contactors by warning against livevoltages on inputs.

Provided below is a description of an illustrative data processingsystem in which embodiments provided herein may be implemented andutilized. Although some of the entities may be depicted as separatecomponents, in some instances one or more of the components may becombined into a single device or location (and vice versa). Similarly,although certain functionality may be described as being performed by asingle entity or component within the system, the functionality may, insome instances, be performed by multiple components or entities (andvice versa). Communication between entities and components may includethe exchange of data or information using electronic messages on anysuitable electronic communication medium as described below. As will beappreciated by one of ordinary skill in the art, these systems may haveonly some of the components described below, or may have additionalcomponents.

FIG. 5 depicts an example block diagram of a data processing system uponwhich the disclosed embodiments may be implemented in certainembodiments. Embodiments may be practiced with various computer systemconfigurations such as hand-held devices, microprocessor systems,microprocessor-based or programmable user electronics, minicomputers,mainframe computers and the like. The embodiments can also be practicedin distributed computing environments where tasks are performed byremote processing devices that are linked through a wire-based orwireless network. FIG. 5 shows one example of a data processing system,such as data processing system 500, which may be used with the presentdescribed embodiments. Note that while FIG. 5 illustrates variouscomponents of a data processing system, it is not intended to representany particular architecture or manner of interconnecting the componentsas such details are not germane to the techniques described herein. Itwill also be appreciated that network computers and other dataprocessing systems which have fewer components or perhaps morecomponents may also be used. The data processing system of FIG. 5 may,for example, a personal computer (PC), workstation, tablet, smartphoneor other hand-held wireless device, or any device having similarfunctionality.

As shown, the data processing system 501 includes a system bus 502 whichis coupled to a microprocessor 503, a Read-Only Memory (ROM) 507, avolatile Random Access Memory (RAM) 505, as well as other nonvolatilememory 506. In the illustrated embodiment, microprocessor 503 is coupledto cache memory 504. System bus 502 can be adapted to interconnect thesevarious components together and also interconnect components 503, 507,505, and 506 to a display controller and display device 508, and toperipheral devices such as input/output (“I/O”) devices 510. Types ofI/O devices can include keyboards, modems, network interfaces, printers,scanners, video cameras, or other devices well known in the art.Typically, I/O devices 510 are coupled to the system bus 502 through I/Ocontrollers 509. In one embodiment the I/O controller 509 includes aUniversal Serial Bus (“USB”) adapter for controlling USB peripherals orother type of bus adapter.

RAM 505 can be implemented as dynamic RAM (“DRAM”) which requires powercontinually in order to refresh or maintain the data in the memory. Theother nonvolatile memory 506 can be a magnetic hard drive, magneticoptical drive, optical drive, DVD RAM, or other type of memory systemthat maintains data after power is removed from the system. While FIG. 5shows that nonvolatile memory 506 as a local device coupled with therest of the components in the data processing system, it will beappreciated by skilled artisans that the described techniques may use anonvolatile memory remote from the system, such as a network storagedevice coupled with the data processing system through a networkinterface such as a modem or Ethernet interface (not shown).

With these embodiments in mind, it will be apparent from thisdescription that aspects of the described techniques may be embodied, atleast in part, in software, hardware, firmware, or any combinationthereof. It should also be understood that embodiments can employvarious computer-implemented functions involving data stored in a dataprocessing system. That is, the techniques may be carried out in acomputer or other data processing system in response executing sequencesof instructions stored in memory. In various embodiments, hardwiredcircuitry may be used independently, or in combination with softwareinstructions, to implement these techniques. For instance, the describedfunctionality may be performed by specific hardware componentscontaining hardwired logic for performing operations, or by anycombination of custom hardware components and programmed computercomponents. The techniques described herein are not limited to anyspecific combination of hardware circuitry and software.

Embodiments herein may also be in the form of computer code stored on acomputer-readable medium. Computer-readable media can also be adapted tostore computer instructions, which when executed by a computer or otherdata processing system, such as data processing system 500, are adaptedto cause the system to perform operations according to the techniquesdescribed herein. Computer-readable media can include any mechanism thatstores information in a form accessible by a data processing device suchas a computer, network device, tablet, smartphone, or any device havingsimilar functionality. Examples of computer-readable media include anytype of tangible article of manufacture capable of storing informationthereon such as a hard drive, floppy disk, DVD, CD-ROM, magnetic-opticaldisk, ROM, RAM, EPROM, EEPROM, flash memory and equivalents thereto, amagnetic or optical card, or any type of media suitable for storingelectronic data. Computer-readable media can also be distributed over anetwork-coupled computer system, which can be stored or executed in adistributed fashion.

Throughout the foregoing description, for the purposes of explanation,numerous specific details were set forth in order to provide a thoroughunderstanding of the invention. It will be apparent, however, to personsskilled in the art that these embodiments may be practiced without someof these specific details. Accordingly, the scope and spirit of theinvention should be judged in terms of the claims which follow as wellas the legal equivalents thereof.

What is claimed is:
 1. A power grid array comprising: a plurality ofgenerators, wherein each of the plurality of generators includes aninterlock output and a load output; a plurality of power output cables,each being associated with a corresponding generator of the plurality ofgenerators, wherein: each of the plurality of power output cablesincludes a safety wire and a load line; the safety wire of each of theplurality of power output cables is connected to the interlock output ofthe corresponding generator; and the load line of each of the pluralityof power output cables is connected to the load output of thecorresponding generator; a power distribution unit including a pluralityof inputs, wherein: each of the plurality of inputs is connected to acorresponding power output cable of the plurality of power outputcables; and the power distribution unit includes an automatic disconnectcontactor operable to electrically disconnect the load line of thecorresponding power output cable from the corresponding generator whenthe corresponding generator is shut down.
 2. The power grid array ofclaim 1, wherein the plurality of generators share an overall electricalload of the power grid array.
 3. The method of claim 2, wherein theoverall electric load is balanced among the plurality of generators inthe power grid array, and wherein one or more of the generators in thepower grid array are automatically shut down based on the overallelectrical load.
 4. The power grid array of claim 1, wherein each of theplurality of generators further includes a controller and a battery,wherein the battery provides DC power to the controller from a DC powerconnector using a DC power receptacle, and wherein each DC powerconnector is coupled to one or more other DC power connectors of othergenerators of the plurality of generators.
 5. The power grid array ofclaim 4, wherein the DC power connectors are coupled together in adaisy-chain fashion.
 6. The power grid array of claim 4, wherein the DCpower connectors provides power to the power distribution unit andcharges batteries of idle generators.
 7. The power grid array of claim1, wherein each of the plurality of generators further includes acontroller and a digital receptacle, wherein the digital receptaclereceives one or more digital signals to communicate data and one or morecontrol signals among and between the plurality of generators.
 8. Thepower grid array of claim 7, wherein the digital receptacles are coupledtogether in a daisy-chain fashion.
 9. The power grid array of claim 8,wherein one of the digital receptacles is coupled to a control input ofthe power distribution unit using a digital paralleling cable.
 10. Thepower grid array of claim 1, wherein the plurality of generators areautomatically synchronized in the power grid array.
 11. The power gridarray of claim 1, wherein one or more of the generators remainoperational while the generator is shut down.
 12. The power grid arrayof claim 1, wherein the load line of the corresponding power outputcable is still coupled to the corresponding generator when electricallydisconnected by the automatic disconnect contactor, and wherein theautomatic disconnect contactor is controlled using the safety wire. 13.A method of operating a power grid array including a plurality ofgenerators and a power distribution unit, the method comprising:providing the plurality of generators, each generator including a loadoutput and an interlock output; providing the power distribution unit,wherein the power distribution unit includes a plurality of inputs, eachinput coupled to an automatic disconnect contactor; providing aplurality of power output cables, each power output cable associatedwith a corresponding generator of the plurality of generators and acorresponding input of the plurality of inputs, wherein each of theplurality of output cables includes a safety wire and a load line; foreach of the plurality of power output cables: connecting a first end ofthe load line to the load output of the corresponding generator;connecting a second end of the load line to the corresponding input ofthe power distribution unit; connecting a first end of the safety wireto the interlock output of the corresponding generator; and connecting asecond end of the safety wire to the automatic disconnect contactorcoupled to the corresponding input, wherein the automatic disconnectcontactor is operable to electrically disconnect the second end of theload line when the corresponding generator is shut down.
 14. The methodof claim 13, wherein the one or more current generators share an overallelectrical load of the power grid array.
 15. The method of claim 13,wherein the overall electric load is balanced among the one or morecurrent generators in the power grid array, and wherein one or more ofthe current generators in the power grid array are automatically shutdown based on the overall electrical load.
 16. The method of claim 13,further comprising: coupling a line from a current generator of the oneor more current generators to the new generator, wherein the line iscoupled to the current generator using a first DC power connector,wherein the new generator further includes a controller, a battery, anda second DC power connector, and wherein the battery provides DC powerto the controller from the second DC power connector using the line. 17.The method of claim 16, wherein the second DC power connector providespower to the power distribution unit and charges batteries of one ormore idle generators of the one or more current generators.
 18. Themethod of claim 13, further comprising: coupling a digital receptacle toa control input of the power distribution unit using a digitalparalleling cable, wherein the new generator further includes acontroller and the digital receptacle, wherein the digital receptaclereceives one or more digital signals to communicate data and one or morecontrol signals among and between the one or more current generators.19. The method of claim 13, wherein the one or more of currentgenerators are automatically synchronized in the power grid array. 20.The method of claim 13, wherein one or more of the current generatorsremain operational when the new generator is shut down.